胶原蛋白及多肽的黏度特性

采用生物酶技术从皮边角余料中提取不同分子量分布范围的胶原蛋白及多肽 ,着重考察了溶液浓度、p H值、温度、存放时间和外加电解质对不同分子量分布的胶原蛋白及多肽的黏度的影响 ,结果表明 :水解胶原蛋白及多肽的黏度与其分子量大小、浓度高低和电解质用量成正比 ,与温度和存放时间成反比 ,随 p H值与等电点的差值的绝对值增加而增加。     

A new zwitterionic surfactant with high interfacial activity and high salt tolerance derived from methyl oleate through an eco-friendly aryl-introducing method

Surfactants, that can reduce the interfacial tension between crude oil and formation water to ultra-low, are needed in tertiary oil recovery. A bio-based zwitterionic surfactant, N-phenylpropanaldehyde epoxy acetal octadecanoicamido propyl-N, N-dimethyl hydroxy sulfonate (PADS), was derived from methyl oleate. In the process of synthesizing PADS, a new reactive site was introduced by epoxidizing methyl oleate and then the benzene ring was introduced by acetalization, which was a greener new method of introducing benzene ring into hydrophobic chains of surfactants. PADS was identified by ESI-MS and NMR, and its interfacial activity was measured by interfacial tensiometer. The results showed that PADS possessed excellent interfacial activity and potential for low-dose application. Under alkali-free conditions, it could reduce the interfacial tension between crude oil and simulated formation water to ultra-low in a wide concentration range (0.005–3 g/L). In addition, although the NaCl concentration was 230 g/L in the system, PADS still had good interfacial activity and could maintain ultra-low oil–water interfacial tension. The protocol of epoxidation and acetalization provides a new feasible path to preparing bio-based surfactants with high interfacial activity.     

大豆多肽的制备及其应用研究

介绍了大豆多肽的组成、生产工艺、功能特性、应用前景、研究现状及其存在的问题,并讨论了大豆多肽苦味的产生原因、影响因素及解决方法。     

AD-1两性离子共聚物的合成和应用

采用过硫酸铵-亚硫酸钠氧化还原体系为引发剂,以2-丙烯酰胺-2-甲基丙磺酸(AMPS)和一种不饱和季铵盐阳离子为单体进行自由基水溶液聚合,生成AD-1两性离子共聚物,并用作酸液稠化剂。通过正交实验设计法,分析了单体含量与配比、反应温度、反应时间及pH对聚合反应的影响,测定了共聚物的特性粘数,评价了在酸液中的增稠性能。结果表明,在45℃、单体总质量分数为25%、阳离子单体加量13%、pH7条件下反应4h所得的共聚物性能较好,特性粘数可达272mL/g,2.5%AD-1共聚物在20%盐酸溶液中表观粘度可达27mPa·s。     

Preparation,characterization and application of zwitterionic polymers and membranes: current developments and perspective

Because of their unique pendant‐side chain structures and excellent properties, zwitterionic polymers and membranes, especially zwitterionic hybrids, have attracted increasing interest in recent years. Presently, they can be potentially applied in such fields as nonlinear optical systems, ionic conduction, biomedical processing and chemical separation. In view of their significance to academia and industrial processes, this review gives a brief summary of current developments in the preparation, characterization and potential application of zwitterionic polymers and membranes. Novel approaches to prepare zwitterionic hybrids are highlighted. The present state and future perspective are also discussed. Hopefully, this review can promote the understanding of zwitterionic hybrid polymers and membranes. Copyright © 2009 Society of Chemical Industry     

Hemocompatible biomaterials of zwitterionic sulfobetaine hydrogels regulated with pH-responsive DMAEMA random sequences

Polyzwitterionic biomaterial with pH-responsive and hemocompatible dual functions is formulated by the copolymerization of 2-(N, N-dimethyl amino) ethyl methacrylate (DMAEMA) sequences and sulfobetaine methacrylate (SBMA) moieties. Hydrogels are salt responsive, due to the interplay between hydrogen bonds formation, ions solvation, and antipolyelectrolyte effect, while DMAEMA sequences provide pH-responsiveness. Their low-fouling nature is demonstrated using plasma proteins and bacteria. Improved hemocompatibility with SBMA content is unveiled by the resistance to platelet and erythrocyte attachment, as well as from delayed plasma clotting time. Overall, this study suggests that dual-functional zwitterionic hydrogels are promising pH-responsive and hemocompatible polymeric biomaterials.     

Complexation‐Induced Biomimetic Long Range Fibrous Orientation in a Rigid‐Flexible Block Copolymer Thermogel

The orientation of the organofibrous structure plays an important role not only in the biomineralization process but also in the extracellular matrix (ECM) of articular cartilage by providing cells with biomechanical cues. Here, it is reported that a long range nanofibrous orientation can be realized by a self‐assembling ionic complex between (+)‐charged amphiphilic peptide block copolymers with a rigid‐flexible block structure (polyalanine‐PLX‐polyalanine; PA‐PLX‐PA) and (‐)‐charged hyaluronic acid (HA). A biomimetic 3D culture system encapsulating chondrocytes is formed by a temperature‐sensitive sol‐to‐gel transition of the PA‐PLX‐PA/HA complex aqueous solution, which provides a compatible microenvironment for the cells. The cell proliferation and biomarker expression for articular cartilage are significantly improved in the PA‐PLX‐PA/HA complex system relative to the PA‐PLX‐PA or the commercially available Matrigel systems. In particular, noticeable cell clustering is observed in the PA‐PLX‐PA/HA complex system with the long range nanofibrous structure. This research suggests a new method for developing a nanofibrous structure using an amphiphilic peptide block copolymer and demonstrates its potential uses as a unique biomimetic cell‐culture matrix.     

Effects of Magnetic Fields on Polymer Liquid Crystals

Abstract

The effects of magnetic fields on polymer liquid crystals (PLCs) are analyzed, dealing in turn with isotropic solutions, lyotropic LCs (including polypeptides, polyribonucleotides and DNA) and thermotropic PLCs (including polyesters and polypeptides). Looking for a common denominator in LC behavior, living systems are also analyzed, including viruses, biological membranes, sperm nuclei, rhodopsin and fibrinogen. Magnetropism is discussed, as are applications of PLC oriented in magnetic fields for the purpose of producing ultra-high modulus materials.     

凝胶过滤色谱法测定3 种不同来源多肽的相对分子质量分布

目的：建立凝胶过滤色谱法测定多肽（如大豆肽、白蛋白多肽、羊胎盘多肽）的相对分子质量分布的方法。方法：采用TSK-GEL G2000SWXL色谱柱（300 mm×7.8 mm,5 μm）、流动相为乙腈-水-三氟乙酸（15∶85∶0.07,V/V）、流速0.6 mL/min、柱温30 ℃、进样体积10 μL、检测波长220 nm。结果：在相对分子质量189.1～12 355之间,相对分子质量对数与保留时间呈线性关系,相关系数为0.995 6,方法精密度、重复性、稳定性良好,准确度高。结论：本方法操作简便快速、灵敏度高、重复性好,适用于多肽类物质相对分子质量分布的检测。     

两性离子催化剂的研究进展

两性离子催化剂按照配体的结构特征和金属元素种类可分为两性离子茂金属配合物、非茂前过渡以及后过渡金属两性离子配合物三大类。两性离子茂金属配合物根据阴离子在配体上所连接区域的不同又可以分为Girdle型、Bridge型和Ring型三种。本文对各类两性离子配合物的合成方法、结构特征和催化反应活性进行了归纳总结,发现两性离子催化剂对催化烯烃聚合表现出较好的活性,而非茂的两性离子配合物不仅是良好的烯烃聚合催化剂,还可以催化多种类型的小分子反应。作为一种新型高效的单组份活性催化剂,目前,有关两性离子催化剂的应用研究还有很多未知的领域有待开发,尤其是在小分子的活化、催化领域。